Plumbing in the Brain: Superficial similarities of vasculature in different parts of the body may mask organ-specific developmental nuances. The vasculature of the brain uniquely has to insulate the organ from insults that the rest of the body must tolerate. Kuhnert et al. (p. 985 ) analyzed the developmental uniqueness of the brain's vasculature through study of a G protein–coupled receptor, GPR124, initially identified by its actions in the vasculature of colon cancer. GPR124 is also involved in normal development of the brain's vasculature. Mice expressing low levels of GPR124 did not develop adequate vasculature in the brain and died from hemorrhages. Mice with too much GPR124 developed a tangled, thin-walled, excessive vasculature in the brain. Although the overexpressing mice survived, they were prone to neurological symptoms such as ataxia. GPR124 seems to control the normal development of the endothelial cells, particularly in the forebrain and ventral neural tube.

VEGF and angiopoietin-1 (Ang1) are two major angiogenic factors being investigated for the treatment of myocardial infarction (MI). Targeting VEGF and Ang1 expression in the ischemic myocardium can increase their local therapeutic effects and reduce possible adverse effects. Adeno-associated viral vectors (AAVs) expressing cardiac-specific and hypoxia-inducible VEGF [AAV-myosin light chain-2v (MLC)VEGF] and Ang1 (AAV-MLCAng1) were coinjected (VEGF/Ang1 group) into six different sites of the porcine myocardium at the peri-infarct zone immediately after ligating the left descending coronary artery. An identical dose of AAV-Cytomegalovirus (CMV)LacZ or saline was injected into control animals. AAV genomes were detected in the liver in addition to the heart. RT-PCR, Western blotting, and ELISA analyses showed that VEGF and Ang1 were predominantly expressed in the myocardium in the infarct core and border of the infarct heart. Gated single-photon emission computed tomography analyses showed that the VEGF/Ang1 group had better cardiac function and myocardial perfusion at 8 wk than at 2 wk after vector injection. Compared with the saline and LacZ controls, the VEGF/Ang1 group expressed higher phosphorylated Akt and Bcl-xL, less Caspase-3 and Bad, and had higher vascular density, more proliferating cardiomyocytes, and less apoptotic cells in the infarct and peri-infarct zones. Thus, cardiac-specific and hypoxia-induced coexpression of VEGF and Ang1 improves the perfusion and function of porcine MI heart through the induction of angiogenesis and cardiomyocyte proliferation, activation of prosurvival pathways, and reduction of cell apoptosis.

According to rodent models of postoperative cognitive decline, activation of the innate immune response following aseptic surgical trauma results in the elaboration of hippocampal proinflammatory cytokines, which are capable of disrupting long-term potentiation, the neurobiologic correlate of memory. The authors hypothesize that hippocampal recruitment of bone marrow-derived macrophages plays a causal role in these processes, resulting in memory dysfunction. Clodrolip injection (liposomal formulation of clodronate) before stabilized tibial fracture under general anesthesia was used to deplete bone marrow-derived macrophages. Systemic inflammation and neuroinflammation were studied on postoperative day 1, and memory in a fear-trace conditioning paradigm was assessed on postoperative day 3. CX3CR1 CCR2 mice were used to identify bone marrow-derived macrophages. Clodrolip effectively depleted splenic CCR2 bone marrow-derived macrophages. It also attenuated the surgery-induced increase of interleukin-6 in the serum and the hippocampus, and prevented hippocampal infiltration of CCR2 cells without affecting the number of CX3CR1 microglia. It did not alter the surgery-induced increase in hippocampal monocyte chemoattractant protein-1, the recruitment signal for CCR2 cells. Clodrolip prevented surgery-induced memory dysfunction, as evidenced by a significant increase in freezing time (29% [95% CI, 21-38%] vs. 48% [95% CI, 38-58%], n = 20, P = 0.004), but did not affect memory in nonsurgical mice. Depletion of bone marrow-derived macrophages prevents hippocampal neuroinflammation and memory dysfunction after experimental tibial fracture. These data suggest that the hippocampal recruitment of bone marrow-derived macrophages is a necessary mechanism in murine postoperative cognitive dysfunction. Interventions designed to prevent its activation and/or migration into the brain may represent a feasible preemptive strategy.

Vascular endothelial growth factor (VEGF) plays important roles in physiological and pathological angiogenesis. Recent studies have demonstrated that direct injection of VEGF protein, plasmid DNA, or an adenoviral vector encoding the VEGF gene into ischemic myocardium or limb can induce collateral blood vessel formation and improve perfusion of the ischemic areas. However, these approaches have limitations ranging from a short-lasting effect to angioma formation. In this study, we investigated the feasibility of using adeno-associated viral (AAV) vectors to deliver VEGF genes to mouse myocardium. A cytomegalovirus promoter was used to drive genes for a human VEGF isoform, VEGF ₁₆₅ , and LacZ. A mouse myocardial ischemic model was generated by ligation of the anterior descending coronary artery. Approximately 10 ¹¹ copies of the AAV-VEGF vector mixed with 10 ¹⁰ copies of AAV-LacZ were injected to one site of normal myocardium and a total of 10 ¹¹ copies of AAV-VEGF were injected to multiple sites of myocardium around the ischemic region. LacZ gene expression was observed up to 3 months after the vector inoculation. After AAV-VEGF inoculation, neoangiogenesis was observed in the ischemic heart model but not in normal heart tissue. An inflammatory-cell infiltration was not observed in the AAV-VEGF- and AAV-LacZ-inoculated hearts, and angioma-like structure was not observed. These results indicated that injection of the AAV vector directly to myocardium could mediate efficient gene transfer and transgene expression and that VEGF gene delivered by AAV vector can induce angiogenesis in ischemic myocardium.